In a small bowl, combine olives, tomato, olive oil, celery, garlic, red wine vinegar, oregano, salt and black pepper.
Cut Italian bread in half crosswise. Spread bottom of cut side with half of olive mixture. Layer on roast beef, Swiss cheese, red peppers, turkey and American cheese. Spread remaining olive mixture over cheese and top with other half of bread.
Wrap tightly in plastic wrap and weigh down with a heavy pot filled with canned goods for at least an hour. Slice into 10 wedges to serve.
